And there are no excuses for that either. Even if you tell them you have a giant dog, you're still wrong because dogs aren't supposed to shit on a porch either.
But most cats are even smaller than dogs. You should tell them you have a Savannah F-1. Those are pretty big. And yeah, I just looked that up on Google.
And because cats shit everywhere it will not be weird when it shits on a porch. Problem solved!